As Per the National Coverage Determination (NCD) for Implantable Automatic Defibrillators (20.4) . CMS mandates that providers bill the Q0 modifier for all primary prevention diagnosis codes to ensure that claims are reported appropriately to the registry. Modifier Q0 is not required to be appended for secondary prevention. (Secondary prevention codes are listed below the table)Q0 - Append this modifier on a category B IDE code (e.g. CPT 33249- Insertion or replacement of permanent implantable defibrillator system, with transvenous lead(s), single or dual chamber) if data is submitted to an FDA-approved category B IDE clinical trial, a trial under the CMS Clinical Trial Policy, or a qualifying data collection system, including approved clinical trials and registries.Modifier Q0 is only required when the ICD was implanted for primary prevention of sudden cardiac death. If the ICD procedure was performed for primary prevention, and modifier Q0 is not appended, coverage for the ICD implantation cannot be established and the service will be denied.For CPT codes 33223, 33224, 33225, 33230, 33231, 33240, 33241, 33244, 33249,33262, 33263, 33264, 33270, 33271, 33272, 33273 & G0448 the claim must be reported with a secondary diagnosis as described below,

ICD-10-CM code I25.2, I25.5, I42.0, I42.6, I42.7 or I42.8 must be billed with one of the following ICD-10-CM codes I50.21, I50.22, I50.23, I50.41, I50.42 or I50.43 (Secondary)